Presently, aircraft parts made from commercial, fiber-reinforced composites or laminates use vacuum-bag or press molding of plies of prepregs containing fibers and polymeric resins. Historically these composites were composed of thermosetting resins. The individually impregnated plies or layers of prepregs were consolidated by the application of heat and pressure by vacuum-bag molding and compaction in an autoclave. In recent years, thermoplastic polymers have been developed which have some benefits over thermoset polymers. The main difference between the two systems is that thermosets require curing, while thermoplastics only require melting, thus saving time in the process.